Canon 30D Metering and AF points

[Craig Thayer]

I photograph with a Canon 30D and Canon 100-400mm IS lens(I will likely add a prime lens soon). I often photograph using spot metering and a center AF point but have had mixed success. Many Chicago area birders using Canon 20D/30D/40D with the same lens use evaluative metering mode and automatic AF point selection with good success.

I would greatly appreciate a discussion regarding the pros and cons of these methods(or any other combination of them) including their usage for single birds versus groups of birds.


Craig Thayer Chicago, IL

[gmax]

I photograph with a Canon 30D and Canon 100-400mm IS lens(I will likely add a prime lens soon). I often photograph using spot metering and a center AF point but have had mixed success. Many Chicago area birders using Canon 20D/30D/40D with the same lens use evaluative metering mode and automatic AF point selection with good success.

I would greatly appreciate a discussion regarding the pros and cons of these methods(or any other combination of them) including their usage for single birds versus groups of birds.


Craig Thayer Chicago, IL

Hello Craig,
there's a discussion going on now in the Technique section, about focussing on birds in flight ... perhaps you'll find it useful.
As far as I'm concerned, I have tried several methods (both re. focussing and metering), and I now prefer using the centre focus point only and partial metering on my 20D ... maybe if you can add some detail on what you feel is hindering your success percentuage, other members will surely add their own advice
Cheers,
Max

[Roy C]

I photograph with a Canon 30D and Canon 100-400mm IS lens(I will likely add a prime lens soon). I often photograph using spot metering and a center AF point but have had mixed success. Many Chicago area birders using Canon 20D/30D/40D with the same lens use evaluative metering mode and automatic AF point selection with good success.

I would greatly appreciate a discussion regarding the pros and cons of these methods(or any other combination of them) including their usage for single birds versus groups of birds.


Craig Thayer Chicago, IL
Another vote for Centre Focus point and Partial metering. I do occasionally use spot but the spot area needs to be right over the bird - if the bird is to small in the frame then I find spot can have some strange results.

[tdodd]

Unless the bird is in constantly changing light then it's manual exposure for me all the way, based on the sunny 16 rule as a starting point and then adjusted to give me the shutter speed I need for the actual lighting conditions. Auto exposure on the fly just doesn't seem like a good plan if the bird will be flying against a constantly changing background, or is so small and lively that you cannot keep it centred in the frame. If you've got a big bird and can track it well then AE will work OK, but personally I would not want my exposure changing just because the background was sky one minute, trees the next, water the next and then dry earth. If the bird is sunlit then it is sunlit. I do not want to have to battle with variable backgrounds throwing off the exposure for my subject.

I'll alternate between centre point and all focus points depending on how easy the bird will be to track and keep centred. Remember with all AF points in use you must secure a lock on the bird with the centre point first and then the other points will help out if the bird slips off the centre. You cannot begin to AF with anything except the centre point. The centre point is where the AF baseline is established. If your bird is on an outer point and your background is over the centre when you start to focus then your camera will focus on the background.

Here's an example where anything other than manual exposure would have simply not worked - the bird was too small to be a useful target for metering and the background was very dark. Unless you can dial in EC in a flash, any autoexposure mode would have overexposed the bird. Manual exposure kept everything easy. This was a sequence of two shots within the space of a second (plus 100% crops). I was actually a bit off with my exposure so both these have been boosted by 1 stop in DPP. Still better than the results I think I would have achieved with autoexposure though.

[Roy C]

Remember with all AF points in use you must secure a lock on the bird with the centre point first and then the other points will help out if the bird slips off the centre. You cannot begin to AF with anything except the centre point. The centre point is where the AF baseline is established. If your bird is on an outer point and your background is over the centre when you start to focus then your camera will focus on the background..
There is another thread running on BF where this is being discussed: http://www.birdforum.net/showthread.php?t=113374 starting at post#13

[tdodd]

There is another thread running on BF where this is being discussed: http://www.birdforum.net/showthread.php?t=113374 starting at post#13
Thanks for the heads-up. I'm only on the Canon forum here so I would not have seen that.

FWIW I've just uploaded an album of BIF shots taken with my 40D at Colchester zoo recently. Every shot here was taken using all focus points and I have included resized full frame images and 100% crops. They're not that great, because the birds were pretty lively and tracking them was a real problem. Many shots are way off centre and in most shots the background is actually pretty busy. Even when focus is off, it is only because the AF has failed to keep up, or because my tracking was simply too poor. I do not see signs anywhere that the AF got confused and switched to the background.

Here's the album, displayed as a slideshow. There are 40 images and 40 crops, representing the results from 2 X 20 minute flying demonstrations....

http://picasaweb.google.co.uk/EezyTiger/BIF40DAndAllAFPointsInUse/photo?authkey=tQzX3FlZxJA#s5198069123532806018

In many respects I wish I'd zoomed in closer but some of the shots were with my 70-200 and I was already at full stretch with that and struggling to keep the birds in the frame at all, much less centred. The problem with the zoo display is that the birds get such short runs it is hard to get a bead on them and then keep up.

[Craig Thayer]

Thnaks to everyone who posted on this thread and the related thread. I look forward to (hopefully) improving my photo skills.


Craig Thayer

[howell7079]

I have only had my 30D for 8 months and have gotten by far the most consistant results using evaluative metering and center point focusing, especially taking pictures of birds in flight.

Lyndon